The stars of Entourage are usually just as tight off-screen as they are on the show, but an alleged sock-stuffing incident during a PEOPLE photoshoot has sparked a playful war of words between Adrian Grenier and Kevin Connolly.

Grenier's gone on the mock-defensive after Connolly appeared on Tuesday's Tonight Show with Conan O'Brien and, after the late night host showed a PEOPLE photo of Grenier, Connolly and costar Jerry Ferrara costumed as the Bee Gees for PEOPLE's Hottest Bachelors issue, Connolly told the audience that Grenier's ample disco-pants bulge came courtesy of a strategically placed sock.

"My question is: how would HE know?" Grenier told PEOPLE at the sixth season premiere party for the HBO hit. "What was he doing looking? And why was Conan looking too? It's weird! I've never scrutinized another man's groin area in my entire life – or his socks, for that matter."

Connolly told O'Brien, “Adrian put a sock [in his pants] … When he was doing it, I said ‘What are you doing?' and he said ‘It's what they did in the '70s." I didn't know that. And the photographer's like 'Adrian, we've got to lose one of the socks.' And all of sudden when the photo came out I'm getting calls from girlfriends of mine, like 'So, Adrian…' And I didn't want to throw him under the bus with the individual girls. I figured I'd wait until I got here on The Tonight Show."

"How many socks are in there?" O'Brien wondered.

"I don't know what kind of show they're doing – It's not a medical show," suggested Grenier (who kept coy on the matter of did he or didn't he) about the on-air appraisal of his anatomy. "The Tonight Show is not a medical show, and Conan should learn that."

But even Entourage costar Kevin Dillon – who says he was "SO jealous" he wasn't part of the shoot – admits he was surprised to see what Grenier was packing in his Barry Gibb gear when he first saw the photo. "I was like 'What, do you have a sock in there?'" Dillon told PEOPLE. "And he actually DID – I had no idea! I said it jokingly."